Method for mapping format identification bits onto a frame which is to be transmitted using a compressed mode

ABSTRACT

A method for mapping format identification bits onto a frame which is to be transmitted using a compressed mode, in which more TFCI points are available than TFCI bits wherein in order to fill the excess TFCI points with bits as well and at the same time to achieve as high a performance capability as possible, it is proposed that the TFCI bits be repeated in a skillful manner for the uplink and/or downlink.

BACKGROUND OF THE INVENTION

The present invention relates to a method for mapping formatidentification bits, that is to say so-called TFCI bits, onto a frame tobe transmitted, particularly onto a compressed frame to be transmittedusing the so-called compressed mode.

Mobile radio technology is subject to rapid development. At the moment,work is being carried out on the standardization of the so-called UMTSMobile Radio Standard (“Universal Mobile Telecommunication System”) forthird-generation mobile radios.

Information to be transmitted via a mobile radio channel is normallytransmitted in the form of a predefined frame and time slot structure. AUMTS frame includes 15 time slots “slots”, with specific systeminformation also being transmitted as well as the actual data withineach frame. This system information includes, in particular, a knownpilot bit sequence or training sequence, which the respective receivercan use to estimate the channel impulse response of the respectivemobile radio channel, power control information in the form of one ormore TPC bits (Transmit Power Control), whose contact is used to controlthe transmission power of the respective receiver, and formatidentification information in the form of so-called TFCI bits (TransportFormat Combination Indicator).

On the basis of the current status of UMTS standardization, a TFCI codeword is provided for each UMTS frame, including ten initially uncodedbits which are then coded using a second-order (32, 10) subcode of theReed-Muller code, and are thus mapped onto a total of 32 bits. Of these32 bits, bit nos. 0 and 16 are then punctured in the normal mode (in thenormal mode or non-compressed mode), so that the TFCI code word nowincludes only 30 TFCI bits, which are then mapped or distributeduniformly with two TFCI bits in each case onto the individual time slotsin the corresponding UMTS frame. These are allocated in such a way thatthe two most significant TFCI bits in the TFCI code word are allocatedto the time slot no. 0 which is transmitted first within the UMTS frame,and the two least significant bits are allocated to the time slot no.14, which is transmitted last within the frame. The more significantTFCI bit is then transmitted before the less significant TFCI bit withinthe individual time slots. The mapping or allocation of the TFCI bits inthe TFCI code word onto or to the individual time slots in a frame isalso referred to as mapping.

The term “puncturing” for the purposes of the present application alsoincludes the removal or non-transmission of specific bits; inparticular, the last bits.

In addition to normal transmission of information in uncompressed form,a compressed mode is also provided for data transmission. In thecompressed mode, the information in the respective frame is transmittedin compressed form; in order to artificially produce a transmission gap,during whose duration the absence of transmitted information can beused, for example, for intermediate-frequency measurements in order toprepare for handover processes, etc.

In the compressed mode, at least eight time slots still must be leftfree per frame. The 30 TFCI bits must, in consequence, be distributedbetween the remaining time slots in the compressed mode. In order toallow this, the time slot format of the uplink control channel DPCCH(Dedicated Physical Control Channel) and of the downlink control channelDPCCH, as well as that of the downlink data channel DPDCH (DedicatedPhysical Data Channel) must be matched.

In this context, various time slot formats have been proposed for theuplink DPCCH control channel for the compressed mode. These can besummarized by the table shown in FIG. 4, in which the number N_(TFCI) ofTFCI bits transmitted per time slot and the total number D of TFCI bitstransmitted per frame are in each case shown for a different number oftime slots or slots transmitted per frame in the compressed mode.

Corresponding proposals for time slot formats for the downlink in thecompressed mode have also been made, which can be summarized by thetables shown in FIG. 5A and FIG. 5B, where FIG. 5A relates to a spreadfactor of between 128 and 512 being used for the correspondingchannelization codes or spread codes, while FIG. 5B relates to spreadfactors of between 4 and 64. Analogously to FIG. 4, these tables eachshow the number N_(TFCI) of TFCI bits transmitted per time slot and thetotal number D of TFCI bits transmitted per frame for a different numberof time slots or slots transmitted per frame in the compressed mode,with a distinction also being drawn in this case between Type A and TypeB transmission.

Since it is desirable to use a standard time slot format for each frame,situations may occur (as is indicated by the individual values for D inFIG. 4 and FIGS. 5A/B) in which more TFCI points are available in eachframe than are actually required for the 30 TFCI bits.

For the uplink, that is to say for transmission from a mobile part to abase station, it has thus been proposed that selected TFCI bits berepeated in the compressed mode; that is to say, that they bereiterated, in order to fill the excess TFCI points, with, inparticular, those bits which are sent immediately after the transmissiongap that occurs in the compressed mode being repeated at free TFCIpoints for this purpose, in order that the repetition is carried out aseffectively as possible. The reason for this is based on the fact thatthe transmission power control is very uncertain immediately after thetransmission gap, so that the probability of a transmission beingsubject to interference is highest immediately after the transmissiongap, so that these bits should be repeated, if possible. The repeatedbits can, in this case, be determined via the following algorithm, wherec_(k) denotes the TFCI bits, d_(k) denotes the repeated bits, D denotesthe number of TFCI points available in total in the frame, and E denotesthe index or the position of that TFCI point which immediately followsthe transmission gap in the compressed mode:d_(D-31)=c_(E mod 30)d_(D-32)=c_((E-1)mod 30)d_(D-33)=c_((E-2)mod 30)

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.d₀=c_((E-(D-31))mod 30)

The bits are allocated to the individual time slots in the compressedframe in a descending sequence, with the TFCI bits c_(k) beingtransmitted first, followed by the repeated bits d_(k), that is to saythe bit c₂₉ (Most Significant Bit (MSB) in the TFCI code word) beingtransmitted as the first bit in the TFCI code word, while do istransmitted as the last bit in the TFCI code word.

For the downlink, that is to say for transmission from a base station toa mobile part, it has in contrast been proposed to fill the free orexcess TFCI points with so-called DTX bits (Discontinuous TransmissionBits) in the compressed mode. A DTX bit, in this case, corresponds to abit which is not transmitted; that is to say, a bit whose energy iszero. A transmission pause with a time duration of one DTX bit is thusinserted at each of the appropriate points in the relevant time slots.

Against the background of the prior art described above, the presentinvention is directed toward a method for mapping TFCI bits onto a framewhich is to be sent in a compressed mode, which makes it possible toimprove the transmission power and the transmission reliability withoutany additional complexity.

SUMMARY OF THE INVENTION

According to the present invention, therefore, it is proposed that theexcess TFCI points be filled by repetition of the TFCI bits followingthe transmission gap, but with these TFCI bits being repeated in thereverse sequence. This procedure is worthwhile since it can be assumedthat those TFCI bits which are sent after the transmission gap have alower bit error rate as the distance from the transmission gapincreases. For this reason, it is better to repeat those TFCI bits whichhave the highest bit error rate owing to their proximity to thetransmission gap in a time slot which is as far away from thetransmission gap as possible.

The present invention is based on the knowledge that, in the compressedmode, the transmission gap interferes with the power control whichstabilizes only as the distance from the transmission gap increases. Thefilling of additional TFCI points with TFCI bits (in the uplink and/ordownlink) or DTX bits (in the downlink) is optimized on the basis ofthis fact. Furthermore, the present invention and exemplary embodimentsare based on the knowledge that it is better to send the previouslypunctured TFCI bits than to repeat TFCI bits which were sent in poorpower control conditions.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the following DetailedDescription of the Invention and the Figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a simplified block diagram of an arrangement for coding,puncturing and mapping TFCI bits onto a UMTS frame which is to be sentusing the so-called compressed mode, which arrangement can be used in atransmitting apparatus according to the present invention.

FIG. 2 shows an illustration to explain the mapping of the TFCI bitsonto a UMTS frame.

FIG. 3 shows an illustration to explain various exemplary embodiments ofthe present invention relating to the compressed mode.

FIG. 4 shows a table listing various known time slot formats for a UMTSframe transmitted via an uplink connection in the compressed mode.

FIGS. 5A and 5B show tables listing various known time slot formats fora UMTS frame transmitted via a downlink connection in the compressedmode.

DETAILED DESCRIPTION OF THE INVENTION

Before describing in any more detail the various exemplary embodimentsaccording to the present invention, the fundamental design of anarrangement for mapping TFCI bits onto a UMTS frame, as shown in FIG. 1,will be explained.

A (32, 10) coder 1 is supplied with uncoded TFCI bits, which are to bemapped onto the respective UMTS frame. In principle, the number ofuncoded TFCI bits is variable and is defined via appropriate signalingat the start of a connection. However, if there are less than tenuncoded TFCI bits, the corresponding TFCI word is filled with zeros tomake a total of ten bits, with the more significant bits being set tozero in this case. This ensures that the (32, 10) coder 1 is alwayssupplied with a TFCI word having ten TFCI bits.

The (32, 10) coder 1 codes the TFCI word supplied to it using asecond-order (32, 10) subcode of the so-called Reed-Muller code. Thecorresponding (31-10) coder 1 is, in this case, structured such that theTFCI code word emitted from the (32, 10) coder 1 is formed by a linearcombination (controlled by the uncoded TFCI bits) of ten different basicsequences.

The TFCI code word which is emitted from the (32, 10) coder 1 and whichnow includes 32 bits is then supplied to a puncturing unit 2, in whichthe bit no. 0 and the bit no. 16 are punctured; that is to say, they areremoved from the TFCI code word. The punctured TFCI code word resultingfrom this now has only 30 TFCI bits.

The 30 TFCI bits are supplied to a unit 3 whose task is to assign thesebits in the normal mode (that is to say, for uncompressed transmission)or in the compressed mode (that is to say, for compressed transmission)to the individual time slots or slots in the respective UMTS frame (seeFIG. 2).

As has already been described, the 30 TFCI bits in the normal mode aredistributed uniformly between the 15 time slots in the respective UMTSframe, with the two most significant TFCI bits no. 29 and no. 28 beingmapped onto the time slot no. 0 which is transmitted first in time,while the two least significant bits no. 1 and no. 0 are mapped onto thetime slot no. 14 which is transmitted last within the frame.

Exactly the same configuration of TFCI bits to be transmitted also can,of course, be achieved in another way. For example, the numbering of thebits is purely a conventional question, and the MSB and LSB also couldbe defined in a different sequence. Furthermore, the puncturingoperations do not need to relate to the bit nos. 0 and 16, since otherbits also may be punctured.

On the basis of another method of representation, the elements of themasks used for the Reed-Mueller code also may be reorganized so that thebits to be punctured may be placed at any desired points; particularlyat the end of the TFCI code word. All these alternative, equivalentforms of representation are likewise within the scope of the presentinvention, even if they are not mentioned explicitly in the followingtext.

However, in the compressed mode and as shown in FIG. 3, there is atransmission gap in the corresponding frame in which no information istransmitted. In the example shown in FIG. 3, this transmission gapcovers the time slots no. 6–8. As has already been described, thisrequires that the time slot format be adapted appropriately so that, incertain of these adapted formats, there are more available TFCI pointsthan TFCI bits (see also FIG. 4 and FIGS. 5A/5B).

In the following text, various options for filling these excess TFCIpoints are proposed both for the uplink and for the downlink, and theexemplary embodiments proposed in the following text for the uplink canalso be used for the downlink. Furthermore, the individual exemplaryembodiments also may be combined with one another.

First of all, a number of exemplary embodiments of the present inventionfor the uplink will be explained in the following text.

According to a first exemplary embodiment, in the situation where thereare more TFCI points than TFCI bits available in the compressed mode, itis proposed that the excess TFCI bits should not be filled immediatelyby repetition, but that the TFCI points which are still unfilled shouldfirst of all be filled with the bits no. 0 and no. 16, which wereoriginally punctured by the puncture unit 2, in the original TFCI codeword. These two bits are preferably placed at the end of thecorresponding UMTS frame. Only after these bits have been mapped ontothe UMTS frame are the TFCI points which still remain free filled byrepetition, and this is carried out analogously to the prior artdescribed initially such that the 30 bits in the TFCI code word aremapped onto the TFCI points which are transmitted first in time, whilethe repeated bits are allocated to the later TFCI points in the frame.

This procedure results in a change to the previously proposed algorithmfor determining the additional TFCI bits d_(k) as follows, where Edenotes the index of the TFCI point which immediately follows thetransmission gap, c_(k), where k=0 . . . 29, denotes the 30 TFCI bits inthe punctured TFCI code word, c₃₀ and c₃₁ denotes the two originallypunctured bits no. 6 and no. 16 in the TFCI code word emitted from thecoder 1, and D denotes the number of TFCI points in the entire frame:d_(D-31)=c_(E mod 30)d_(D-32)=c_((E-1)mod 30)d_(D-33)=c_((E-2)mod 30)

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.d₂=c_((E-(D-33))mod 30)d₁=c₃₁d₀=c₃₀

For the example shown in FIG. 3, this results in the following procedurefor mapping the TFCI bits onto the respective frame. Since thetransmission gap covers three time slots, only twelve time slots aresent, so that, on the basis of the table shown in FIG. 4, three TFCIbits should be transmitted in each time slot, with a total of 36 TFCIbits being transmitted in the entire frame.

According to the algorithm described above, the TFCI bits c₂₉ to c₁₂ areinitially distributed between the first time slots no. 0 to no. 5 andthe TFCI bits c₁₁ to c₀ are initially distributed between the next timeslots no. 9 to no. 12. Thus, once all the TFCI bits in the puncturedTFCI code word have been allocated, the TFCI bits c₁₁, c₁₀, c₀₉ arerepeated in time slot no. 13, and the originally punctured TFCI bits c₃₀and c₃₁ are mapped onto the last time slot no. 14, with the TFCI bit c₀₈also being repeated in the time slot no. 14.

This procedure is advantageous since it is better to send the previouslypunctured bits in the TFCI (32, 10) code word than to repeat bits whichhave been sent in poor conditions, in terms of power control, owing tothe transmission gap which exists in the compression mode.

The exemplary embodiment described above also can be modified such thatthe originally punctured bits are not placed in the last time slot inthe UMTS frame but are sent directly after the transmission gap.Furthermore, as in the prior art, the TFCI bits which then immediatelyfollow the transmission gap are repeated. This procedure has theadvantage that those bits which are normally punctured in any case aresent at the TFCI points whose transmission conditions are “poor.”

Based on the example shown in FIG. 3 and according to this exemplaryembodiment, the TFCI bits c₂₉ to c₁₂ are initially distributed betweenthe first time slots no. 0 to no. 5. The TFCI points in the time slotno. 9 are filled with the originally punctured bits c₃₀ and c₃₁ as wellas the TFCI bit c₁₁. The TFCI bits c₁₀ to c₂ are assigned to the timeslots no. 10 to 12. The time slot no. 13 is filled by the TFCI bits c₀₁and c₀. Those TFCI points which are then still available in the timeslots no. 13 and no. 14 are filled, as has already been described above,by the TFCI bits which immediately follow the transmission gap, so thatbit c₃₀ is repeated in time slot no. 13, and the bits c₃₁, c₁₁, c₁₀ arerepeated in the time slot no. 14.

It may be expected that those TFCI bits which are sent after thetransmission gap have a lower bit error rate as their distance from thetransmission gap increases, since the power control can stabilize onceagain as the distance from the transmission gap increases. A furthergood option for filling the available TFCI points in the compressed modeis to repeat those TFCI bits which are transmitted immediately after thetransmission gap and which have the greatest error probability in thattime slot which is furthest away from the transmission gap. It is thusadvantageous to repeat those TFCI bits which immediately follow thetransmission gap in the reverse sequence (and not in the same sequence,as before).

The algorithm described initially for determining the repeated bitsd_(k) in consequence change as follows:d_(D-31)=c_((E-(D-31))mod 30)d_(D-32)=c_((E-(D-32))mod 30)d_(D-33)=c_((E-(D-33))mod 30)

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.d₁=c_((E-1)mod 30)d₀=c_(E mod 30)

For the example shown in FIG. 3, this results in the TFCI bits C₂₉ toc₁₂ being initially distributed between the first time slots no. 0 tono. 5, and the TFCI bits c₁₁ to c₀ being initially distributed betweenthe next time slots no. 9 to no. 12. Thus, once all the TFCI bits in thepunctured TFCI code word have been allocated, those TFCI bits which thenimmediately follow the transmission gap are repeated in the reversesequence in order to fill those TFCI points which are still free; thatis to say, the TFCI bits c₀₆, c₀₇, c₀₈ are repeated in the time slot no.13, and the TFCI bits c₀₉, c₁₀, c₁₁ are repeated in the time slot no.14.

It is particularly advantageous for this exemplary embodiment to becombined with the first exemplary embodiment, that is to say for the twooriginally punctured TFCI bits c₃₀ and c₃₁ to be sent in the last timeslot, while those TFCI bits which immediately follow the transmissiongap are repeated in the reverse sequence in order to fill the free TFCIpoints. The following algorithm is therefore used to determine how theTFCI points d_(k) are filled:d_(D-31)=c_((E-(D-33))mod 30)d_(D-32)=c_((E-(D-34))mod 30)

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.d₂=c_(E mod 30)d₁=c₃₁d₀=c₃₀

For the example shown in FIG. 3, this results in the TFCI bits c₂₉ toc₁₂ being initially distributed between the first time slots no. 0 tono. 5 and the TFCI bits c₁₁ to c₀ being additionally distributed betweenthe next time slots no. 9 to no. 12. Thus, once all the TFCI bits in thepunctured TFCI code word have been allocated, those TFCI bits which thenimmediately follow the transmission gap are repeated in the reversesequence, and the originally punctured bits c₃₀ and c₃₁ are sent in thelast time slot in order to fill the TFCI points which are still free;that is to say, the TFCI bits c₀₈, c₀₉, c₁₀ are repeated in the timeslot no. 13, while the originally punctured TFCI bits c₃₀ and c₃₁ aswell as the repeated TFCI bit c₁₁ are assigned to the time slot no. 14.

As has already been described, the TFCI bits in the TFCI (32, 10) codeword, which has been punctured twice, are usually distributed betweenthe first TFCI points in the respective frame in the compressed mode,while those TFCI points which are then still available are filled byrepetition. If at least 32 TFCI points are available, depending on theformat respectively chosen for the compressed mode (see FIG. 4), thereis a further option for filling the TFCI points in which the entireunpunctured (32, 10) code word can be sent immediately, and in which anyTFCI points which are still free are only then filled by repetition. Inthis case, the TFCI code word supplied from the coder 1 would retain itsoriginal length and sequence since, as indicated by dashed lines in FIG.1, no puncturing is carried out.

For the example shown in FIG. 3, this results in the TFCI bits c₃₀ toc₁₅, c₃₁ and c₁₄ being initially distributed between the first timeslots no. 0 to no. 5, and the TFCI bits c₁₃ to c₀₂ being initiallydistributed between the next time slots no. 9 to no. 12. In this case,it should be noted that c₃₀ denotes the bit no. 0 and c₃₁ denotes thebit no. 16 in the unpunctured TFCI code word emitted from the coder 1(FIG. 2 shows only the punctured TFCI code word). Those TFCI bits c₀₁and c₀ which still remain are sent, first of all in the time slot no.13. Those TFCI points which are then still free in the time slot no. 13and in the time slot no. 14 are filled by repetition, in which case thepreviously described exemplary embodiments can be used once again forthe repetition. In the present situation, those TFCI bits whichimmediately follow the transmission gap are once again repeated, so thatthe TFCI bit c₁₃ is repeated in the time slot no. 13, while the TFCIbits c₁₂ to c₁₀ are repeated in the time slot no. 14.

In the following text, exemplary embodiments of the present inventionfor filling those TFCI points for the downlink which are available inthe compressed mode will be explained.

As has already been explained, so-called DTX bits can be used for thispurpose.

Within the scope of the present invention, it is now proposed that theseDTX bits should not be distributed between those TFCI points which stillremain at the end of the respective frame after transmission of thepunctured TFCI code word, but that these DTX bits should be transmittedimmediately after the transmission gap that occurs in the compressedmode. As such, as many DTX bits as there are excess TFCI points in theframe are transmitted immediately after the transmission gap. Theremaining TFCI points in the frame are filled with the bits of thepunctured TFCI code word.

This procedure has the advantage that the DTX bits are used for thoseTFCI points in which the probability of transmission being subject tointerference is greatest, owing to the proximity to the transmissiongap.

If, as is shown in FIG. 3, a frame is transmitted with a transmissiongap covering three time slots (by way of example, for a spread factor of256) according to the table shown in FIG. 5A, four TFCI points areavailable in each time slot (the downlink frame structure is assumed tobe of Type A). On the basis of the exemplary embodiment described above,the TFCI bits c₂₉ to c₀₆ in the punctured TFCI code word are accordinglydistributed between the time slots no. 0 to no. 5. 16 DTX bits are sentin the time slots no. 9 to no. 12, while two DTX bits are sent, first ofall, in the time slot no. 13, followed by the TFCI bits c₀₅ and c₀₄.Finally, the remaining TFCI bits c₀₃ to c₀ in the punctured TFCI codeword are sent in the last time slot no. 14.

Should there be fewer time slots after the transmission gap than thenumber required for the DTX bit, those DTX bits which cannot betransmitted after the transmission gap can be allocated to the timeslots before the transmission gap. In this case, they may, in principle,be distributed in any desired way, in which case it is advantageous todistribute the DTX bits as uniformly as possible. As a furtherembodiment variant, only some of the DTX bits may be insertedimmediately after the transmission gap, with the remaining DTX bitsbeing allocated to the other time slots before and after thetransmission gap. This is particularly advantageous when more time slotsare available after the transmission gap than are required forstabilization of the power control.

One specific embodiment of the present invention provides for 30 bits ofthe TFCI code word to be mapped initially onto the frame to betransmitted, in the compression mode. Furthermore, two originallypunctured bits or two bits which are not intended to be transmitted inthe normal mode (during normal operation and in the uncompressed mode)are mapped onto the frame to be transmitted. If, particularly in theuplink, the number of format identification points available in thecorresponding compressed frame exceeds the limit of 32 formatidentification points, then TFCI bits are mapped repeatedly onto theframe to be transmitted; in particular, those TFCI bits which are sentshortly after the transmission gap are mapped repeatedly onto the frameto be transmitted (they are repeated). This repeated mapping is, in thiscase, carried out in reverse sequence to that in which these TFCI bitswere first mapped.

If, particularly in the downlink, the number of format identificationpoints available in the corresponding compressed frame exceeds the limitof 32 format identification points, then DTX bits are mapped repeatedlyonto the frame to be transmitted.

Finally, it should be mentioned once again that the exemplaryembodiments described above with reference to the uplink also can, inprinciple, be used for the downlink. Furthermore, the present inventionhas been described above on the basis of the use in a mobile radiotransmitter. The present invention also may, of course, be extended tomobile radio receivers, which shall be designed appropriately forreception and evaluation of a signal which is processed according to thepresent invention and is then transmitted.

Indeed, although the present invention has been described with referenceto specific embodiments, those of skill in the art will recognize thatchanges may be made thereto without departing from the spirit and scopeof the present invention as set forth in the hereafter appended claims.

1. A method for transmitting in a wireless network, comprising mappingformat identification bits onto a frame which is being transmitted usinga compressed mode, the method comprising the steps of: sendinginformation, contained within a frame which is being transmitted usingthe compressed mode, compressed in time such that there is atransmission gap, which is not filled with information, within thecompressed frame; mapping format identification bits in the compressedmode onto a specific number of format identification points which areavailable in a corresponding compressed frame, with the specific numberbeing greater than a number of format identification bits; mapping theformat identification bits following the transmission gap repeatedlyafter a first mapping of the format identification bits ontocorresponding format identification points, in order to fill all theformat identification points with a format identification bit; andmapping, after the first mapping of the format identification bits, theformat identification bits following the transmission gap repeatedly ina reverse sequence, in order to fill the format identification pointswhich are still unfilled in the compressed frame after the first mappingprocess with a format identification bit.
 2. A method transmitting in awireless network as claimed in claim 1, wherein, during the firstmapping process, the format identification bits are mapped onto theformat identification points in the compressed frame which are beingtransmitted first in time.
 3. A method for transmitting in a wirelessnetwork as claimed in claim 2, wherein, during the first mappingprocess, the format identification bits are mapped according to arespectively associated significance onto the corresponding formatidentification points in the compressed frame, with a most significantformat identification bit being mapped onto the identification pointwhich is being transmitted first in time in the compressed frame.
 4. Amethod for transmitting in a wireless network as claimed in claim 1,wherein the method is carried out before sending the compressed framevia an uplink connection in a UMTS mobile radio system.
 5. A method fortransmitting in a wireless network as claimed in claim 1, wherein themethod is carried out before sending the compressed frame via a downlinkconnection in a UMTS mobile radio system.